A longitudinal adjuster of this type has become known from U.S. Pat. No. 7,521,924 B2. To detect a position of the seat, a sensor, which is arranged on a seat rail fixed to the seat, cooperates with a flat magnet, which has a predetermined pole arrangement, arranged in the seat rail fixed to the vehicle structure at the bottom thereof. The magnet is hereby arranged at one end of the seat rail. The magnetic field detected by the sensor changes due to the moving of the magnet.
Another sensor array with a Hall sensor has become known from U.S. Pat. No. 7,439,735 B2. In this case, the sensor array is arranged outside of the seat rail fixed to the seat and cooperates with an edge area, which is bent upwards and inwards, of the seat rail fixed to the vehicle structure, whose end it detects. In this case an air gap between the sensor array and the edge area of the seat rail fixed to the vehicle structure to be detected is between 0.5 mm and 2.75 mm.